DNA-based analysis of protein variants reveals different genetic variability of the paralogous equine ß-lactoglobulin genes LGB1 and LGB2

Role of genes related to performance and reproduction of Thoroughbreds in training and breeding - A review

Thoroughbreds have been selected for speed and stamina since the 1700s. This selection resulted in structural and functional system-wide adaptations that enhanced physiological characteristics for outstanding speed of 61-71 kph (38-44 mph) between 1,000 and 3,200 m (5 furlongs - 2 miles). At present, horseracing is still an economically important industrial sector, therefore intensive research is underway to explore genes that allow the utilisation of genetic abilities and are significant in breeding and training. This study aims to provide an overview of genetic research and its applicability related to Thoroughbreds.

Beta-lactoglobulin-nutrition allergen and nanotransporter of different nature ligands therapy with therapeutic action

β-lactoglobulin is one of the nutrition allergens present in the milk of many mammals, with the exception of human. This protein belongs to the family of lipocalins, consisting of nine antiparallel β-strands (β-A to β-I) and one α-helix. This structure allows it to serve as a nanotransporter of various nature ligands in a pH dependent manner, which allows us to confidently consider it as a reliable carrier of drugs directly into the intestine, bypassing the destructive acidic environment of the stomach. Based on the latest data, this review describes the currently known methods of reducing the allergenicity of beta-lactoglobulin, as well as the mechanisms and methods of forming complexes of this protein with ligands, which emphasizes its importance and versatility and explains the growing interest in studying its properties in recent decades, and also opens up prospects for its practical application in medicine and pharmaceuticals.

Genes encoding equine β-lactoglobulin (LGB1 and LGB2): Polymorphism, expression, and impact on milk composition

β-lactoglobulin is one of the most abundant milk whey proteins in many mammal species, including the domestic horse. The aim of this study was to screen for polymorphism in the equine LGB1 and LGB2 gene sequences (all exons, introns, and 5’-flanking region) and to assess potential relationship of particular genotypes with gene expression levels (measured in milk somatic cells) and milk composition traits (protein, fat, lactose, and total β-lactoglobulin content). Direct DNA sequencing analysis was performed for twelve horse breeds: Polish Primitive Horse (PPH), Polish Coldblood Horse (PCH), Polish Warmblood Horse (PWH), Silesian, Hucul, Fjording, Haflinger, Shetland Pony, Welsh Pony, Arabian, Thoroughbred, and Percheron—and revealed the presence of 83 polymorphic sites (47 and 36 for LGB1 and LGB2 genes, respectively), including eight that were previously unknown. Association analysis of the selected polymorphisms, gene expression, and milk composition traits (conducted for the PPH, PCH, and PWH breeds) showed several statistically significant relationships; for example, the two linked LGB1 SNPs (rs1143515669 and rs1144647991) were associated with total milk protein content (p < 0.01). Our study also confirmed that horse breed had significant impact on both gene transcript levels (p < 0.01) and on milk LGB content (p < 0.05), whereas an influence of lactation period was seen only for gene relative mRNA abundances (p < 0.01).

The Identification of Novel Single-Nucleotide Polymorphisms of Equine Beta-Lactoglobulin and Lactotransferrin Genes

Lactoferrin (LTF), also called lactotransferrin, is an iron-binding protein and member of transferrin family, whereas β-LG is an important milk protein and belongs to the ligand-binding protein family of lipocalins and binds retinol. Beta-lactoglobulin (β-LG) is a major whey protein and it is a member of lipocalins family. β-LG is also known as a major allergen reason of cow milk protein allergy. Yet, no information has been reported about β-LG and LTF genes in donkeys. In this study, the genetic variation of β-LG and LTF genes were analyzed via DNA sequencing in 77 donkeys, which were individuals reared in Thrace region of Turkey. Four novel SNPs are identified as g.12887G>A, g.12973G>A, g.12654G>A, and g.13057T>C in the third intron region of β-LG gene and a genetic variant g.272719G>A in the 14th intron of LTF gene. The DNA sequences of β-LG and LTF genes in donkeys are reported for the first time in this study and these sequences were deposited to NCBI GenBank database, with the accession number MK125015 and MK211165, respectively. These variations may have an effect on milk yield and content in donkeys, so further investigations are needed to prove this hypothesis and these may be candidate SNPs for donkey breeding.